In 1991, a Texas oil tycoon built a massive, totally enclosed terrarium in the Arizona desert containing self-sustaining replicas of Earth’s biomes, including “a mini-rainforest, a desert, a savannah, an ocean with a living coral reef†populated by “hundreds of carefully selected plants and animal species.†Among those species were eight humans, who were tasked with quarantining inside the experimental environment — named Biosphere 2 — for two years. The mystery of Biosphere 2, and its surviving “Biospherians,†is the subject of the documentary Spaceship Earth from director Matt Wolf, which unearths much of the disappeared data and media surrounding this fascinating, large-scale experiment. Spaceship Earth will be released by Neon for Hulu and digital download on May 8. Until then, check out this clip featuring interviews, blueprints, and models of Biosphere 2. Why did they name it Biosphere 2? Because “Biosphere 1 is the Earth.â€